grep.c

   1 #include "cache.h"
   2 #include "grep.h"
   3 #include "xdiff-interface.h"
   4
   5 void append_header_grep_pattern(struct grep_opt *opt, enum grep_header_field field, const char *pat)
   6 {
   7         struct grep_pat *p = xcalloc(1, sizeof(*p));
   8         p->pattern = pat;
   9         p->origin = "header";
  10         p->no = 0;
  11         p->token = GREP_PATTERN_HEAD;
  12         p->field = field;
  13         *opt->pattern_tail = p;
  14         opt->pattern_tail = &p->next;
  15         p->next = NULL;
  16 }
  17
  18 void append_grep_pattern(struct grep_opt *opt, const char *pat,
  19                          const char *origin, int no, enum grep_pat_token t)
  20 {
  21         struct grep_pat *p = xcalloc(1, sizeof(*p));
  22         p->pattern = pat;
  23         p->origin = origin;
  24         p->no = no;
  25         p->token = t;
  26         *opt->pattern_tail = p;
  27         opt->pattern_tail = &p->next;
  28         p->next = NULL;
  29 }
  30
  31 static void compile_regexp(struct grep_pat *p, struct grep_opt *opt)
  32 {
  33         int err = regcomp(&p->regexp, p->pattern, opt->regflags);
  34         if (err) {
  35                 char errbuf[1024];
  36                 char where[1024];
  37                 if (p->no)
  38                         sprintf(where, "In '%s' at %d, ",
  39                                 p->origin, p->no);
  40                 else if (p->origin)
  41                         sprintf(where, "%s, ", p->origin);
  42                 else
  43                         where[0] = 0;
  44                 regerror(err, &p->regexp, errbuf, 1024);
  45                 regfree(&p->regexp);
  46                 die("%s'%s': %s", where, p->pattern, errbuf);
  47         }
  48 }
  49
  50 static struct grep_expr *compile_pattern_or(struct grep_pat **);
  51 static struct grep_expr *compile_pattern_atom(struct grep_pat **list)
  52 {
  53         struct grep_pat *p;
  54         struct grep_expr *x;
  55
  56         p = *list;
  57         switch (p->token) {
  58         case GREP_PATTERN: /* atom */
  59         case GREP_PATTERN_HEAD:
  60         case GREP_PATTERN_BODY:
  61                 x = xcalloc(1, sizeof (struct grep_expr));
  62                 x->node = GREP_NODE_ATOM;
  63                 x->u.atom = p;
  64                 *list = p->next;
  65                 return x;
  66         case GREP_OPEN_PAREN:
  67                 *list = p->next;
  68                 x = compile_pattern_or(list);
  69                 if (!x)
  70                         return NULL;
  71                 if (!*list || (*list)->token != GREP_CLOSE_PAREN)
  72                         die("unmatched parenthesis");
  73                 *list = (*list)->next;
  74                 return x;
  75         default:
  76                 return NULL;
  77         }
  78 }
  79
  80 static struct grep_expr *compile_pattern_not(struct grep_pat **list)
  81 {
  82         struct grep_pat *p;
  83         struct grep_expr *x;
  84
  85         p = *list;
  86         switch (p->token) {
  87         case GREP_NOT:
  88                 if (!p->next)
  89                         die("--not not followed by pattern expression");
  90                 *list = p->next;
  91                 x = xcalloc(1, sizeof (struct grep_expr));
  92                 x->node = GREP_NODE_NOT;
  93                 x->u.unary = compile_pattern_not(list);
  94                 if (!x->u.unary)
  95                         die("--not followed by non pattern expression");
  96                 return x;
  97         default:
  98                 return compile_pattern_atom(list);
  99         }
 100 }
 101
 102 static struct grep_expr *compile_pattern_and(struct grep_pat **list)
 103 {
 104         struct grep_pat *p;
 105         struct grep_expr *x, *y, *z;
 106
 107         x = compile_pattern_not(list);
 108         p = *list;
 109         if (p && p->token == GREP_AND) {
 110                 if (!p->next)
 111                         die("--and not followed by pattern expression");
 112                 *list = p->next;
 113                 y = compile_pattern_and(list);
 114                 if (!y)
 115                         die("--and not followed by pattern expression");
 116                 z = xcalloc(1, sizeof (struct grep_expr));
 117                 z->node = GREP_NODE_AND;
 118                 z->u.binary.left = x;
 119                 z->u.binary.right = y;
 120                 return z;
 121         }
 122         return x;
 123 }
 124
 125 static struct grep_expr *compile_pattern_or(struct grep_pat **list)
 126 {
 127         struct grep_pat *p;
 128         struct grep_expr *x, *y, *z;
 129
 130         x = compile_pattern_and(list);
 131         p = *list;
 132         if (x && p && p->token != GREP_CLOSE_PAREN) {
 133                 y = compile_pattern_or(list);
 134                 if (!y)
 135                         die("not a pattern expression %s", p->pattern);
 136                 z = xcalloc(1, sizeof (struct grep_expr));
 137                 z->node = GREP_NODE_OR;
 138                 z->u.binary.left = x;
 139                 z->u.binary.right = y;
 140                 return z;
 141         }
 142         return x;
 143 }
 144
 145 static struct grep_expr *compile_pattern_expr(struct grep_pat **list)
 146 {
 147         return compile_pattern_or(list);
 148 }
 149
 150 void compile_grep_patterns(struct grep_opt *opt)
 151 {
 152         struct grep_pat *p;
 153
 154         if (opt->all_match)
 155                 opt->extended = 1;
 156
 157         for (p = opt->pattern_list; p; p = p->next) {
 158                 switch (p->token) {
 159                 case GREP_PATTERN: /* atom */
 160                 case GREP_PATTERN_HEAD:
 161                 case GREP_PATTERN_BODY:
 162                         if (!opt->fixed)
 163                                 compile_regexp(p, opt);
 164                         break;
 165                 default:
 166                         opt->extended = 1;
 167                         break;
 168                 }
 169         }
 170
 171         if (!opt->extended)
 172                 return;
 173
 174         /* Then bundle them up in an expression.
 175          * A classic recursive descent parser would do.
 176          */
 177         p = opt->pattern_list;
 178         opt->pattern_expression = compile_pattern_expr(&p);
 179         if (p)
 180                 die("incomplete pattern expression: %s", p->pattern);
 181 }
 182
 183 static void free_pattern_expr(struct grep_expr *x)
 184 {
 185         switch (x->node) {
 186         case GREP_NODE_ATOM:
 187                 break;
 188         case GREP_NODE_NOT:
 189                 free_pattern_expr(x->u.unary);
 190                 break;
 191         case GREP_NODE_AND:
 192         case GREP_NODE_OR:
 193                 free_pattern_expr(x->u.binary.left);
 194                 free_pattern_expr(x->u.binary.right);
 195                 break;
 196         }
 197         free(x);
 198 }
 199
 200 void free_grep_patterns(struct grep_opt *opt)
 201 {
 202         struct grep_pat *p, *n;
 203
 204         for (p = opt->pattern_list; p; p = n) {
 205                 n = p->next;
 206                 switch (p->token) {
 207                 case GREP_PATTERN: /* atom */
 208                 case GREP_PATTERN_HEAD:
 209                 case GREP_PATTERN_BODY:
 210                         regfree(&p->regexp);
 211                         break;
 212                 default:
 213                         break;
 214                 }
 215                 free(p);
 216         }
 217
 218         if (!opt->extended)
 219                 return;
 220         free_pattern_expr(opt->pattern_expression);
 221 }
 222
 223 static char *end_of_line(char *cp, unsigned long *left)
 224 {
 225         unsigned long l = *left;
 226         while (l && *cp != '\n') {
 227                 l--;
 228                 cp++;
 229         }
 230         *left = l;
 231         return cp;
 232 }
 233
 234 static int word_char(char ch)
 235 {
 236         return isalnum(ch) || ch == '_';
 237 }
 238
 239 static void show_line(struct grep_opt *opt, const char *bol, const char *eol,
 240                       const char *name, unsigned lno, char sign)
 241 {
 242         if (opt->null_following_name)
 243                 sign = '\0';
 244         if (opt->pathname)
 245                 printf("%s%c", name, sign);
 246         if (opt->linenum)
 247                 printf("%d%c", lno, sign);
 248         printf("%.*s\n", (int)(eol-bol), bol);
 249 }
 250
 251 static void show_name(struct grep_opt *opt, const char *name)
 252 {
 253         printf("%s%c", name, opt->null_following_name ? '\0' : '\n');
 254 }
 255
 256 static int fixmatch(const char *pattern, char *line, regmatch_t *match)
 257 {
 258         char *hit = strstr(line, pattern);
 259         if (!hit) {
 260                 match->rm_so = match->rm_eo = -1;
 261                 return REG_NOMATCH;
 262         }
 263         else {
 264                 match->rm_so = hit - line;
 265                 match->rm_eo = match->rm_so + strlen(pattern);
 266                 return 0;
 267         }
 268 }
 269
 270 static int strip_timestamp(char *bol, char **eol_p)
 271 {
 272         char *eol = *eol_p;
 273         int ch;
 274
 275         while (bol < --eol) {
 276                 if (*eol != '>')
 277                         continue;
 278                 *eol_p = ++eol;
 279                 ch = *eol;
 280                 *eol = '\0';
 281                 return ch;
 282         }
 283         return 0;
 284 }
 285
 286 static struct {
 287         const char *field;
 288         size_t len;
 289 } header_field[] = {
 290         { "author ", 7 },
 291         { "committer ", 10 },
 292 };
 293
 294 static int match_one_pattern(struct grep_opt *opt, struct grep_pat *p, char *bol, char *eol, enum grep_context ctx)
 295 {
 296         int hit = 0;
 297         int saved_ch = 0;
 298         regmatch_t pmatch[10];
 299
 300         if ((p->token != GREP_PATTERN) &&
 301             ((p->token == GREP_PATTERN_HEAD) != (ctx == GREP_CONTEXT_HEAD)))
 302                 return 0;
 303
 304         if (p->token == GREP_PATTERN_HEAD) {
 305                 const char *field;
 306                 size_t len;
 307                 assert(p->field < ARRAY_SIZE(header_field));
 308                 field = header_field[p->field].field;
 309                 len = header_field[p->field].len;
 310                 if (strncmp(bol, field, len))
 311                         return 0;
 312                 bol += len;
 313                 saved_ch = strip_timestamp(bol, &eol);
 314         }
 315
 316  again:
 317         if (!opt->fixed) {
 318                 regex_t *exp = &p->regexp;
 319                 hit = !regexec(exp, bol, ARRAY_SIZE(pmatch),
 320                                pmatch, 0);
 321         }
 322         else {
 323                 hit = !fixmatch(p->pattern, bol, pmatch);
 324         }
 325
 326         if (hit && opt->word_regexp) {
 327                 if ((pmatch[0].rm_so < 0) ||
 328                     (eol - bol) <= pmatch[0].rm_so ||
 329                     (pmatch[0].rm_eo < 0) ||
 330                     (eol - bol) < pmatch[0].rm_eo)
 331                         die("regexp returned nonsense");
 332
 333                 /* Match beginning must be either beginning of the
 334                  * line, or at word boundary (i.e. the last char must
 335                  * not be a word char).  Similarly, match end must be
 336                  * either end of the line, or at word boundary
 337                  * (i.e. the next char must not be a word char).
 338                  */
 339                 if ( ((pmatch[0].rm_so == 0) ||
 340                       !word_char(bol[pmatch[0].rm_so-1])) &&
 341                      ((pmatch[0].rm_eo == (eol-bol)) ||
 342                       !word_char(bol[pmatch[0].rm_eo])) )
 343                         ;
 344                 else
 345                         hit = 0;
 346
 347                 if (!hit && pmatch[0].rm_so + bol + 1 < eol) {
 348                         /* There could be more than one match on the
 349                          * line, and the first match might not be
 350                          * strict word match.  But later ones could be!
 351                          * Forward to the next possible start, i.e. the
 352                          * next position following a non-word char.
 353                          */
 354                         bol = pmatch[0].rm_so + bol + 1;
 355                         while (word_char(bol[-1]) && bol < eol)
 356                                 bol++;
 357                         if (bol < eol)
 358                                 goto again;
 359                 }
 360         }
 361         if (p->token == GREP_PATTERN_HEAD && saved_ch)
 362                 *eol = saved_ch;
 363         return hit;
 364 }
 365
 366 static int match_expr_eval(struct grep_opt *o,
 367                            struct grep_expr *x,
 368                            char *bol, char *eol,
 369                            enum grep_context ctx,
 370                            int collect_hits)
 371 {
 372         int h = 0;
 373
 374         switch (x->node) {
 375         case GREP_NODE_ATOM:
 376                 h = match_one_pattern(o, x->u.atom, bol, eol, ctx);
 377                 break;
 378         case GREP_NODE_NOT:
 379                 h = !match_expr_eval(o, x->u.unary, bol, eol, ctx, 0);
 380                 break;
 381         case GREP_NODE_AND:
 382                 if (!collect_hits)
 383                         return (match_expr_eval(o, x->u.binary.left,
 384                                                 bol, eol, ctx, 0) &&
 385                                 match_expr_eval(o, x->u.binary.right,
 386                                                 bol, eol, ctx, 0));
 387                 h = match_expr_eval(o, x->u.binary.left, bol, eol, ctx, 0);
 388                 h &= match_expr_eval(o, x->u.binary.right, bol, eol, ctx, 0);
 389                 break;
 390         case GREP_NODE_OR:
 391                 if (!collect_hits)
 392                         return (match_expr_eval(o, x->u.binary.left,
 393                                                 bol, eol, ctx, 0) ||
 394                                 match_expr_eval(o, x->u.binary.right,
 395                                                 bol, eol, ctx, 0));
 396                 h = match_expr_eval(o, x->u.binary.left, bol, eol, ctx, 0);
 397                 x->u.binary.left->hit |= h;
 398                 h |= match_expr_eval(o, x->u.binary.right, bol, eol, ctx, 1);
 399                 break;
 400         default:
 401                 die("Unexpected node type (internal error) %d", x->node);
 402         }
 403         if (collect_hits)
 404                 x->hit |= h;
 405         return h;
 406 }
 407
 408 static int match_expr(struct grep_opt *opt, char *bol, char *eol,
 409                       enum grep_context ctx, int collect_hits)
 410 {
 411         struct grep_expr *x = opt->pattern_expression;
 412         return match_expr_eval(opt, x, bol, eol, ctx, collect_hits);
 413 }
 414
 415 static int match_line(struct grep_opt *opt, char *bol, char *eol,
 416                       enum grep_context ctx, int collect_hits)
 417 {
 418         struct grep_pat *p;
 419         if (opt->extended)
 420                 return match_expr(opt, bol, eol, ctx, collect_hits);
 421
 422         /* we do not call with collect_hits without being extended */
 423         for (p = opt->pattern_list; p; p = p->next) {
 424                 if (match_one_pattern(opt, p, bol, eol, ctx))
 425                         return 1;
 426         }
 427         return 0;
 428 }
 429
 430 static int grep_buffer_1(struct grep_opt *opt, const char *name,
 431                          char *buf, unsigned long size, int collect_hits)
 432 {
 433         char *bol = buf;
 434         unsigned long left = size;
 435         unsigned lno = 1;
 436         struct pre_context_line {
 437                 char *bol;
 438                 char *eol;
 439         } *prev = NULL, *pcl;
 440         unsigned last_hit = 0;
 441         unsigned last_shown = 0;
 442         int binary_match_only = 0;
 443         const char *hunk_mark = "";
 444         unsigned count = 0;
 445         enum grep_context ctx = GREP_CONTEXT_HEAD;
 446
 447         if (buffer_is_binary(buf, size)) {
 448                 switch (opt->binary) {
 449                 case GREP_BINARY_DEFAULT:
 450                         binary_match_only = 1;
 451                         break;
 452                 case GREP_BINARY_NOMATCH:
 453                         return 0; /* Assume unmatch */
 454                         break;
 455                 default:
 456                         break;
 457                 }
 458         }
 459
 460         if (opt->pre_context)
 461                 prev = xcalloc(opt->pre_context, sizeof(*prev));
 462         if (opt->pre_context || opt->post_context)
 463                 hunk_mark = "--\n";
 464
 465         while (left) {
 466                 char *eol, ch;
 467                 int hit;
 468
 469                 eol = end_of_line(bol, &left);
 470                 ch = *eol;
 471                 *eol = 0;
 472
 473                 if ((ctx == GREP_CONTEXT_HEAD) && (eol == bol))
 474                         ctx = GREP_CONTEXT_BODY;
 475
 476                 hit = match_line(opt, bol, eol, ctx, collect_hits);
 477                 *eol = ch;
 478
 479                 if (collect_hits)
 480                         goto next_line;
 481
 482                 /* "grep -v -e foo -e bla" should list lines
 483                  * that do not have either, so inversion should
 484                  * be done outside.
 485                  */
 486                 if (opt->invert)
 487                         hit = !hit;
 488                 if (opt->unmatch_name_only) {
 489                         if (hit)
 490                                 return 0;
 491                         goto next_line;
 492                 }
 493                 if (hit) {
 494                         count++;
 495                         if (opt->status_only)
 496                                 return 1;
 497                         if (binary_match_only) {
 498                                 printf("Binary file %s matches\n", name);
 499                                 return 1;
 500                         }
 501                         if (opt->name_only) {
 502                                 show_name(opt, name);
 503                                 return 1;
 504                         }
 505                         /* Hit at this line.  If we haven't shown the
 506                          * pre-context lines, we would need to show them.
 507                          * When asked to do "count", this still show
 508                          * the context which is nonsense, but the user
 509                          * deserves to get that ;-).
 510                          */
 511                         if (opt->pre_context) {
 512                                 unsigned from;
 513                                 if (opt->pre_context < lno)
 514                                         from = lno - opt->pre_context;
 515                                 else
 516                                         from = 1;
 517                                 if (from <= last_shown)
 518                                         from = last_shown + 1;
 519                                 if (last_shown && from != last_shown + 1)
 520                                         fputs(hunk_mark, stdout);
 521                                 while (from < lno) {
 522                                         pcl = &prev[lno-from-1];
 523                                         show_line(opt, pcl->bol, pcl->eol,
 524                                                   name, from, '-');
 525                                         from++;
 526                                 }
 527                                 last_shown = lno-1;
 528                         }
 529                         if (last_shown && lno != last_shown + 1)
 530                                 fputs(hunk_mark, stdout);
 531                         if (!opt->count)
 532                                 show_line(opt, bol, eol, name, lno, ':');
 533                         last_shown = last_hit = lno;
 534                 }
 535                 else if (last_hit &&
 536                          lno <= last_hit + opt->post_context) {
 537                         /* If the last hit is within the post context,
 538                          * we need to show this line.
 539                          */
 540                         if (last_shown && lno != last_shown + 1)
 541                                 fputs(hunk_mark, stdout);
 542                         show_line(opt, bol, eol, name, lno, '-');
 543                         last_shown = lno;
 544                 }
 545                 if (opt->pre_context) {
 546                         memmove(prev+1, prev,
 547                                 (opt->pre_context-1) * sizeof(*prev));
 548                         prev->bol = bol;
 549                         prev->eol = eol;
 550                 }
 551
 552         next_line:
 553                 bol = eol + 1;
 554                 if (!left)
 555                         break;
 556                 left--;
 557                 lno++;
 558         }
 559
 560         free(prev);
 561         if (collect_hits)
 562                 return 0;
 563
 564         if (opt->status_only)
 565                 return 0;
 566         if (opt->unmatch_name_only) {
 567                 /* We did not see any hit, so we want to show this */
 568                 show_name(opt, name);
 569                 return 1;
 570         }
 571
 572         /* NEEDSWORK:
 573          * The real "grep -c foo *.c" gives many "bar.c:0" lines,
 574          * which feels mostly useless but sometimes useful.  Maybe
 575          * make it another option?  For now suppress them.
 576          */
 577         if (opt->count && count)
 578                 printf("%s%c%u\n", name,
 579                        opt->null_following_name ? '\0' : ':', count);
 580         return !!last_hit;
 581 }
 582
 583 static void clr_hit_marker(struct grep_expr *x)
 584 {
 585         /* All-hit markers are meaningful only at the very top level
 586          * OR node.
 587          */
 588         while (1) {
 589                 x->hit = 0;
 590                 if (x->node != GREP_NODE_OR)
 591                         return;
 592                 x->u.binary.left->hit = 0;
 593                 x = x->u.binary.right;
 594         }
 595 }
 596
 597 static int chk_hit_marker(struct grep_expr *x)
 598 {
 599         /* Top level nodes have hit markers.  See if they all are hits */
 600         while (1) {
 601                 if (x->node != GREP_NODE_OR)
 602                         return x->hit;
 603                 if (!x->u.binary.left->hit)
 604                         return 0;
 605                 x = x->u.binary.right;
 606         }
 607 }
 608
 609 int grep_buffer(struct grep_opt *opt, const char *name, char *buf, unsigned long size)
 610 {
 611         /*
 612          * we do not have to do the two-pass grep when we do not check
 613          * buffer-wide "all-match".
 614          */
 615         if (!opt->all_match)
 616                 return grep_buffer_1(opt, name, buf, size, 0);
 617
 618         /* Otherwise the toplevel "or" terms hit a bit differently.
 619          * We first clear hit markers from them.
 620          */
 621         clr_hit_marker(opt->pattern_expression);
 622         grep_buffer_1(opt, name, buf, size, 1);
 623
 624         if (!chk_hit_marker(opt->pattern_expression))
 625                 return 0;
 626
 627         return grep_buffer_1(opt, name, buf, size, 0);
 628 }